若fx=x/x^2-x+3  則f'x=?我理解的是：若f(x)=x/(x^2-x+3)  則f'(x)=?答案是：f'(x)=(3-x^2)/(x^2-x+3)^2

函數(shù)y=xcosx-sinx的導(dǎo)數(shù)為?答案是：y'=x*sinx

f(x)=x(x+1)(x+2)×...×(x+n),則f'(0)=?答案是：f'(x)=(x+1)*(x+2)*...*(x+n)+x*(x+2)*...*(x+n)+x*(x+1)*(x+3)*...*(x+n)+.+x*(x+1)*(x+2)*(x+4)*...*(x+n) 當(dāng)x=0時(shí),除了(x+1)*(x+2)*...*(x+n)等于n!外其他項(xiàng)都有x所以等于0,所以f'(0)=n!

函數(shù)y=x-cosx/x+cosx在點(diǎn)x=2處的導(dǎo)數(shù)為?答案是：y'=1+(x*sinx+cosx)/x^2-sinx,當(dāng)x=2時(shí),y'=1-0.5*sin2+0.25*cos2

函數(shù)y=x^2sinx的導(dǎo)數(shù)為?答案是：y'=2x*sinx+x^2*cosx

f(x)=In(根號(hào)下x^2+1)的導(dǎo)數(shù)為?答案是：f'(x)=x/(x^2+1)

fx=(2x+a)^2,且f'(2)=20.則a=?答案是：f'(x)=4*(2x+a),f'(2)=20,所以a=1